Three-dimensional (3D) graphics are graphics that show objects in three dimensions, instead of two dimensions, and are used in movies using special effects, geological analysis, and architecture or car designing using computer aided design (CAD). Recently, 3D graphics are being used to construct game screens.
To produce 3D graphics, 3D graphics systems break an object represented by lots of dots into polygons, e.g., triangles, comprising a plurality of pixels, perform interpolation on pixels included in each polygon through rasterization, and perform rendering (or presentation) of the 3D graphic. Conventional 3D graphics systems perform the rasterization in an order determined by considering pixel coherence within a triangle. For instance, conventional 3D graphics systems rasterize pixels forming a polygon in a span order. In other words, when a 3D graphics system generates pixels forming a triangle in a downward order, it performs rasterization of the triangle in the same order, i.e., in downward order.
The conventional 3D graphics systems consider only pixel coherence within a polygon when performing polygon rasterization. In other words, pixel coherence between polygons is not considered during the rasterization of the polygons. Consequently, when the 3D graphics systems move over to another polygon, the hit ratio of cache memory decreases and the performance of the 3D graphics systems deteriorates.